On behalf of the Registrant and pursuant to Rule 497 under the Securities
Act of 1933, as amended, attached for filing are exhibits containing interactive data format risk/return summary information that mirrors the risk/return summary information in the 497 filing, dated December 11, 2012 to the prospectus for the
iShares Barclays GNMA Bond Fund. The purpose of this filing is to submit the 497 dated December 11, 2012 in XBRL.

If you have any questions
regarding this filing, please contact Benjamin Haskin of Willkie Farr & Gallagher LLP at (202) 303-1124 or me at (415) 670-7987.